This invention relates to X ray characterization of materials using diffraction and fluorescence analysis.
Although material synthesis has become more sophisticated in order to produce combinatorially synthesized compounds, analysis of such materials has not kept pace. A combinatorially synthesized material will often have a continuous gradient, rather than a sequence of discontinuous plateaus, in the relative concentration of one or more substances, and use of a broad-brush analysis of local concentration fraction(s) will not suffice to characterize the material. This is especially true for characterization of thin films, where standard transmission and/or reflection analyses may be inadequate to characterize changing concentrations on a small scale.
What is needed is an approach that allows characterization of thin films and similar structures where the relative concentration of one or more material constituents may follow a gradient or other similar pattern. Preferably, the approach should be flexible enough to characterize relative concentrations, gradients and structures on a size scale as low as fractions of a micron.
These needs are met by the invention, which uses capillary optics combined with X-ray diffraction analysis and X-ray fluorescence analysis to characterize and analyze thin films and similar material structures that may have relative concentration gradients. A capillary optic produces an X-ray beam spot on a target site of a combinatorial material, and diffraction and fluorescence signals are obtained simultaneously at a selected beam energy. For a given beam energy, the location and angular orientation of the target site are varied in a selected manner to obtain the concentration index of one or more constituents of the material, as a function of target site location, and of the diffraction peak position, height and width. The performance can be improved by removal of an energy E monochromator for the X-ray detector and, simultaneously, reduction of a representative diameter of the capillary.